execgen: add overloads for INTERVAL / INT4 and INTERVAL / INT2

Vectorized overloads for `INTERVAL / INT4` and `INTERVAL / INT2`
expressions have been added. The omission of these overloads caused
errors only in rare cases because usually these expressions are retyped
to `INTERVAL / INT8` by the optimizer
[here](https://github.com/cockroachdb/cockroach/blob/583efd3cd9c7198bac935bb81a7a598e5849a269/pkg/sql/opt/optbuilder/scalar.go#L218).

Fixes #70738

Release note (bug fix): A bug has been fixed which caused errors in rare
cases when trying to divide `INTERVAL` values by `INT4` or `INT2`
values.